in there, but it's unclear if this is even using/adding to the SA score or to amavisd-new, or directly into postfix. I would like to have them add to the SA score, so it doesn't block mail, but just makes it go into the user's Junk folder by default, serverwide.

I'm somewhat saddened by how overly complex SA made it to add RBLs. It's like I'm writing in Erlang again.
You should just have 1 file with all of them, with a score value behind each and that should be enough.
Considering blocking at the MTA (postfix) would just be a 1 or 0 delivery for DNSBLs, it's an insane 'upgrade' to have to write complex rules for each.